Could someone explain this about USPS Autofill----

This question has to do with having to put "00000" into other. I first got my shopping cart up and running and for several months I did not need to use the "00000' to cause an error. Then the error pop up requiring me to use the "00000" and still does. I then downloaded my cart and used it to clone five other shopping carts for my dealers changing information and fresh database to match their name & address etc. this was in July. So far all the dealer shopping carts do not need "00000" to make USPS autofill to work. All the databases are cloned from the same tables (empty records).

Does anyone have ideas that may lead to a fix so we won't have to use "00000"

Thanks